反应详情

To a solution of ethyl 2-methyl acetoacetate (1, 4.00 mL, 27.7 mmol) in toluene (60 mL) was added ammonium acetate (12.83 g, 166 mmol) and acetic acid (10 mL) under N2 at room temperature. The reaction was heated to reflux for 4 h. A Dean stark trap was placed in between the reaction flask and a reflux condenser. Most of the solvents and NH4OAc were removed through a Dean-stark trap. The residue was dissolved in EtOAc (200 mL), washed with water (3×50 mL), and brine (50 mL). Dried over MgSO4, filtered, the solvent was removed under reduced pressure, and distilled at 80° C. 1.0 mm/Hg to afford 2.6 g of 2 as a 4.5:1 mixture of product and starting material which was taken on to the next step without further purification.

1. temperatureThe reaction was heated
2. temperatureto reflux for 4 h
3. customMost of the solvents and NH4OAc were removed through a Dean-stark trap
4. dissolutionThe residue was dissolved in EtOAc (200 mL)
5. washwashed with water (3×50 mL), and brine (50 mL)
6. dry with materialDried over MgSO4
7. filtrationfiltered
8. customthe solvent was removed under reduced pressure
9. distillationdistilled at 80° C